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Commercial Building Permit (New Construction / Tenant Improvement) in Unincorporated Ada County, Idaho

Required for all new commercial, industrial, and multi-family buildings (three or more units), tenant improvements, remodels, and change-of-use projects in unincorporated Ada County. Governed by the 2018 International Building Code (IBC) as adopted by Ada County Ordinance #919. Applications submitted digitally by email.

Verified 2026-06-29 · Source

When you need this permit

  • Required for new commercial/industrial buildings, multi-family structures (3+ units), tenant improvements, and change-of-occupancy projects
  • Submit complete digital PDF application package (application form + all plan sheets as individual files, not in a zip) by email to mechanical@adacounty.id.gov
  • Commercial Building Permit application form required
  • Full plan set drawn to scale and dimensioned; not all items apply to all structures
  • Post-frame and steel buildings require stamped engineering including foundation design
  • Structural calculations may be required by the plans examiner during review for non-standard materials or non-prescriptive construction

Required documents

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Fee schedule

Building permit feeCredit card payments: 2.4% convenience fee (minimum $2); e-checks: $3.00 flat rate.
Valuation-based per Ada County 2025 Fee Schedule (Resolution 3149, effective November 2025); see Building-Fees.pdf at adacounty.id.gov/developmentservices/permitting-division/fees/

Review timeline

Plan reviewTypical estimate — confirm current times with the Unincorporated Ada County building department
~10–30 business days

How long did your Commercial Building Permit (New Construction / Tenant Improvement) permit actually take in Unincorporated Ada County?

Anonymous — one question, no email. Answers are combined and only shown once at least 5 people have reported.

Inspection process

  1. 1

    Footing / Foundation

    Request by 4:30 PM by phone or before midnight by email for next-day scheduling

  2. 2

    Framing / Structural

    After structural framing complete and before wall cover

  3. 3

    Final

    All work complete per approved plans; Certificate of Occupancy issued

See the full Unincorporated Ada County inspection guide — scheduling & re-inspection fees →

Tips

  • Submit each document as a separate PDF file. Do not merge into a single file or compress into a zip archive — zips take longer to process.
  • Post-frame and steel buildings always require stamped engineering from an Idaho-licensed design professional, including foundation design.
  • Electrical work falls under the Idaho Division of Building Safety (DBS), not Ada County Building Division.

Frequently asked questions

Unincorporated Ada County requires a commercial building permit (new construction / tenant improvement) for: Required for new commercial/industrial buildings, multi-family structures (3+ units), tenant improvements, and change-of-occupancy projects; Submit complete digital PDF application package (application form + all plan sheets as individual files, not in a zip) by email to mechanical@adacounty.id.gov; Commercial Building Permit application form required; Full plan set drawn to scale and dimensioned; not all items apply to all structures; Post-frame and steel buildings require stamped engineering including foundation design; Structural calculations may be required by the plans examiner during review for non-standard materials or non-prescriptive construction. If your project isn't listed, confirm with Ada County Development Services — Building Division at 208-287-7900 before starting work.

In Unincorporated Ada County, the published Building permit fee is: Valuation-based per Ada County 2025 Fee Schedule (Resolution 3149, effective November 2025); see Building-Fees.pdf at adacounty.id.gov/developmentservices/permitting-division/fees/. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Plan review for a commercial building permit (new construction / tenant improvement) in Unincorporated Ada County typically runs 10–30 business days. This is an estimate, not a published figure — confirm current review times with Ada County Development Services — Building Division at 208-287-7900.

You'll need: Commercial Building Permit Application (.docx); Full Commercial Plan Set. See the required-documents checklist on this page for details on each.

Unincorporated Ada County requires 3 inspection(s) for a commercial building permit (new construction / tenant improvement), in order: Footing / Foundation, Framing / Structural, Final. Schedule each through Ada County Development Services — Building Division (208-287-7900).

Submit your commercial building permit application and all plan documents as individual PDF files by email to mechanical@adacounty.id.gov. The Permitting Team will contact you for payment once the application is confirmed complete. Accepted payment: e-check ($3 flat) or credit card (2.4% convenience fee, minimum $2). Source: adacounty.id.gov/developmentservices/permitting-division/applications-forms-templates/

Unincorporated Ada County, Idaho has adopted: 2018 International Building Code (IBC) — adopted via Ordinance #919, Ada County Code; 2018 International Residential Code (IRC) — adopted via Ordinance #919; 2018 International Existing Building Code (IEBC) — adopted via Ordinance #919; 2018 International Energy Conservation Code (IECC) — Commercial Provisions; Residential as modified by Idaho Statute Title 39 Chapter 41; adopted via Ordinance #919; 2018 International Mechanical Code (IMC) — adopted via Ordinance #919; 2018 International Fuel Gas Code (IFGC) — adopted via Ordinance #919; 2018 International Urban-Wildland Interface Code (IUWIC) — adopted via Ordinance #919; 2018 International Swimming Pool and Spa Code (ISPSC) — adopted via Ordinance #919. Local amendments apply — see the Unincorporated Ada County overview page for the full list.

Sources & verification

Verified against official sources. Last reviewed 2026-06-29.

Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Unincorporated Ada County building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.

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